Screed chair



Sept. 30, 1941.

FIB,

A c. MABRY 2,257,421

SCREED CHAIR I Filed Oct. 7, 1939 Ill!! MMMMW 3 Sheets-Sheet 1 Sept. 30, 1941. -A. c. MABRY SCREED CHAIR Filed Oct. 7, 1939 3 Sheets-Sheet 2 .EID. El.

Sept. .30, 1941.

I A. c. MABRY SCREED CHAIR Filed Oct. 7, 1939 3 Sheets-Sheet 3 FI [3 1n.-

FIB.11.

Patented Sept. 30, 1941 UNITED STATES PATENT OFFICE SCREED CHAIR Allen Chester'Mabry, College Park, Ga. Application October 7, 1939, Serial No. 298,487 1 Claim. (01. 72-128) My invention consists in a new and useful improvement in screed chairs and is designed to produce a device which is simple and sturdy in construction wherewith ordinary screed pipes maybe quickly and .easilyadjusted to provide for their use in screeding cement floors or slabs. The particularly novel and useful feature of my improved chair is the fact that it consists of only two parts, one the base element which consists of a plate provided with depending lateral ribs havingfour feet for supportingthe device, and

the other the supporting element in which is re- 1 ceived the screed pipe supported by the chair.

The base element is positioned upon the surface on which the concrete floor or slab is to be laid, and the supporting element. properly adjusted relativeto the base element is supported thereby. The particularly valuable feature of my invention is that it provides a chair which can be set or placed upon the slab form, without being attached in any Way to the same. This eliminates any marring of the underside of the finished concrete slab and also eliminates the necessity of pointing up holes in the finished surface on the bottom of the concrete slab. Neither does my chair mar or cut into the form work. My device saves the expense of boring holes in the slab form and nailing anything to the form. Due

Fig. 2 is a side elevation of the set-up shown in Fig. 1. I

Fig. 3 is an end elevation of one of my improved screed chairs, the screed pipe being shown to the fact that my chair is merely set or placed upon the slab form, the labor required is greatly reduced. Dueto the wide base provided by the four legs of my chair, it is very stable and is not subject to being bent sideways or knocked out of place. No matter how thin material is used for forms, my chair is adaptable. It is especially valuable where forms are built for exposed concrete, since ther are no holes left in the concrete which must be later pointed up, and where thin material, such as plywood and prestwood are used for concrete molds. After the cement has been laid, the base element of my chair remains therein, and the supporting element is extricated therefrom.

While I have illustrated in the drawings filed herewith and have hereinafter fully described two specific embodiments of my invention, it is to be distinctly understood that I do not consider my invention limited to said specific embodiments, but refer for its scope to the claim appended hereto.

Fig. 1 is an end elevation illustrating the use of my improved screed chairs supporting a pair or screed pipes and the screed straight edge thereon, the pipes being shown in section.

in section, showing the screeded cement thereabout.

Fig. 4 is a view similar to Fig. 3, afterthe extrication of the removable element of my chair.

Fig. 5 is a view similar to Figs. 3 and 4, after the cavity left by the removable element has been filled with cement. 1

Fig. 6 is an end elevation of my improved screed chair. 1

Fig. 7 is a side elevation.

Fig. 8 is a top plan view. Fig. 9 is a view similar to Fig. 3, illustrating a modified form of my improved screed chair, with the screeded cement thereabout.

Fig. 10 is a side elevation of the set-up shown in Fig. 9, the co-acting parts of the modified form of chair being shown in section.

Fig. 11 is a top plan view of the screeded cement, after the removal of the screed pipe from the chair, the modified form of chair being indicated in dotted lines.

Fig. 12 is a view similar to Fig. 11, after the extrication of the removable parts of the modified form of chair from the screeded cement.

As illustrated in the drawings, my improved screed chair has a rectangular base plate I provided with two depending lateral ribs 2 from each end of each of which projects outwardly a leg 3 disposed at an angle of about 45 to the horizontal plane of the plate I. The plate I has a centrally disposed threaded orifice 4 through which is threaded the stem 5 terminating in a semi-circular pipe holder 6. As illustrated in Figs. 1 and 2, when a plurality of chairs C are properly positioned on the form upon which the concrete is to be laid, and are properly adjusted so that their holders 6 are at the proper height, a screed pipe P is received in the holders 6. In like manner, a second series of chairs C are positioned and adjusted to receive therein the pipe P. When the cement F has been poured,'it can be screeded by the screed straight edge S supported on the accurately adjusted P, P, thus producing the efiect illustrated in Fig. 3. The pipes P and P are then removed from the cement and the removable elements of each of the screed chairs 0 and C, consisting of the holder 6 and stem 5, can be removed by rotation of the element until the stem 5 runs free from the plate I, and the element is then extricated from cavity 1 in the cement. producing the efi'ect illustrated in Fig. 4. The grooves left by the pipes P and P and the cavities! are then filled with cement and the surface smoothed to produce the effect'illustrated in Fig. 5.

The modified form of my improved screed chair, illustrated in Figs. 9, 10, 11 and 12, has the base plate I, ribs 2, legs 3, threaded stem 5 and pipe holder 6. In this form of my chair, the plate 1 has a central bore 8 and a depending sleeve 9 aligned therewith. The stem 5 is passed through the bore 8 and sleeve 9 and has threaded on it the nut I0 bearing upon the top of the plate 1. When my modified form of screed. Adjustment of the chair is made simply by turning the adjusting nut on the stem until chair is used, and the pipe P has been removed" from the screeded cement, leaving the groove H,

shown in Fig. 11, the removable element consisting of the holder 6 and stem '5 with'the nut l0 thereon is extricated by beingv lifted vertically.

the required height is obtained. After the cement is poured, a level can be quickly put on the 'screed'and the chair re-adjusted so as to take care of any sag, and the cementcan then be absolutely leveled up. As pointed out, this adjustment is possible, without removing the screed. When this operation is completed, the screed pipes are removed and, the holders are simply lifted out of the chair, leaving the base portion of the chair in place. As a'result, there is a minimum disturbance of the concrete.

A great advantage of my improved chair is that the entire operation, in its use, is performed on top of the forms for the cement, and another great advantage is that my chair can be adjusted through several inches of adjustment,

through the cement, leaving the transverse shown Fig. 12; Thegrooves H and 12- and the bore I 3 are then-filled with cement and the surface smoothed.

, M-y modified form of chair is designed-so that it may be readily re-adj-usted to thedesired level after slabs are poured andthe forms have taken their deflection or sag, thus making it possible to get a more nearly level floor than would be by the use of screed chairs which do not have this adjustable feature. My chair is designed to overcome the condition resulting fromth'e fact that no matter how strongly forms may be built they will settle and sag to some extent when the concrete is poured into them. In particular, my chair is adjustable after the pouring of concrete has begun and in making such adjustment it is not necessary, with my chair, to remove the thus. making one size of'chair serve for a variety of thicknesses of concrete.

bore therethrough; a pair of depending lateral ribs on two of the opposite edges of said plate,

respectively; a leg extended outwardly and plate concentric: with said bore; a threaded stem slidably received through said bore insaid sleeve, and. provided on its upper end witha semi-aid cular pipe holder; and a nut on said stem supportedby saidplate.

. ALLEN CHESTER MABRY.

, Having described my invention, what I claim in a screed chair, the combination of a rec-.- tangular plate provided with a centrally disposed 

